The DVI (Digital Visual Interface) standard is a standard for a graphics card communicating with a monitor. The DVI standard adopts transmission minimized differential signaling (TMDS) for data transmission between the graphics card and the monitor. Digital signals (including control and data information) generated by a graphics card are sent from a transmitting end through a TMDS channel (including four data lines: three data signals (RGB) and a clock signal) to a receiving end. After decoding the digital signals, the decoded signals are transferred to a digital display circuit for displaying an image on the monitor.
There are various situations (e.g., different transmission line lengths, high and low frequencies, and so on) during the process of signal transmission so that it is inappropriate for the circuits at the receiving end using the same setting to receive data under different situations. Moreover, because the transmitted data are image data, the receiving end is not able to know what the input data are and whether the input data are correct. The receiving end thus can't make the optimized adjustment corresponding to the present situation.
A conventional data recovery method for improving the signal quality at the receiving end is disclosed in U.S. Pat. No. 5,905,769. This method, however, can't effectively make the optimized adjustment in accordance with the present situation.